<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>fasong</button>
</body>

</html>
<script>
    const btns = document.getElementsByTagName('button');
    let x = null;
    //标识变量
    let isSending = false;
    btns[0].onclick = function() {
        if (isSending) x.abort();
        x = new XMLHttpRequest();
        isSending = true;
        x.open('GET', 'http://127.0.0.1:8080/srca')
        x.send();
        x.onreadystatechange = function() {
            if (x.readyState === 4) {
                isSending = false;
            }
        }
    }
</script>